The Cathedral preserves one of the first developed iconostases of the 15th century including 42 icons created by Andrei Rublev and painters of his team. The famous “Trinity”, which is displayed in the Tretyakov Gallery now, was painted by Andrei Rublev for this iconostasis. Its place to the right of the Royal Doors is occupied by a replica painted by N.A. Baranov. In the south-eastern corner of the Cathedral there is a silver tomb with a chased pattern and a text from “The Life of St. Sergius”. It is the shrine with the relics of Sergius of Radonezh. It was made at the end of the 16th century by a group of 14 silversmiths including Russian and foreign craftsmen. At the 18th century, a silver ciborium was installed on four pillars over the ciborium. It was made by David Priff to the design of Caravaque.
The restoration of the Trinity Cathedral began after the foundation of the Museum on the territory of the Trinity-St. Sergius Lavra. It went on in the course of several decades. The Cathedral was cleared of the rough subsequent structures: in 1925, the clumsy northern parvis was dismantled, in 1954, the external walls and the dome were cleared of canvas which was glued in the 18th century. By 1966 the restoration determined and returned the most expressive view of the monument preserving the dome and the zakomars of the 16th century. The clearance and restoration of the icons in the iconostasis began in 1918 and practically finished in the 1970s